710

 This is JavaScript, more exactly JQuery, that hides an element and shows it at the press
 of a button.
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 This goes on the <head> tag:
 <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
 this goes at end of the <body> tag:
 $("#id_of_submitbutton").click(function()
 { alert("Button code executed.");
 });
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 https://tinyurl.com/yhxr8cjn